Mold treating apparatus



June 8, 1965 H, H HARRls 3,187,393

MOLD TREATING APPARATUS Filed July l2, 1965 3 Sheets-Sheet l June 8, 1965 H. H. HARRIS 3,187,393

MOLD TREATING APPARATUS Filed July 12, 1965 y s sheets-sheet 2 INVENTOR. #Fmr ry. #e ceq June 8, 1965 H. H. HARRIS MOLD TREATING APPARATUS 3 sheets-smet 3f Filed July 12, 1965 INVENTOR. #emv n. 04u13 Patented June 8, 1965 3,187,393 MLD TREATENG APPARATUS Henry H. Harris, 6 Accolay Way, Champaign, lil. Filed July 12, 1963, Ser. No. 294,59@ 12 Ciaims. (Ci. 22--41) The present invention relates generally to improvements in the production of molds. In particular, it relates to an improved apparatus for tamping or ramming sand about a pattern attendant the formation of a mold thereof.

The conventional practice in producting sand molds includes the steps of surrounding a pattern carried by a support plate with a flask, depositing sand in the ilask and over the pattern, and then packing or tamping the sand in the iask about the pattern to produce a dense, hard and stable mold having a cavity accurately complementing the pattern upon removal thereof. The tamping is an important element in the procedure and one which greatly effects the character of the mold and hence the quality of the casting. The tamping step is commonly accomplished by ramming by hand or with compressed air driven rammers. Alternatively, the sand is squeezed by means of pneumatic or hydraulic pressure, a combination of the ramming and squeezing being generally employed. Such procedures, and others followed in the industry, are laborious and time consuming and require, the use of skilled labor. They are thus expensive and often result in molds lacking in uniformity and quality and consequently produce inferior castings. The squeeze type machine is expensive and of limited application, being unsatisfactory for use with intricate patterns and characterized by the tendency of the sand to bridge and compact vertically to the detriment of the resulting mold. Many types of semi-automatic tamping devices and mechanisms have been proposed but these involve inflexible arrangements which produce molds of inferior quality and otherwise leave much to be desired. Y

It is, therefore, a principal object of the present invention to provide an improved mold producing apparatus.

Another object of the present invention is to provide an improved apparatus for packing and tamping a granular mold material such as sand about a mold pattern.

Still another object of the present invention is to provide an improved sand mold tamping apparatus which produces a dense, hard, stable and uniform mold' accurately and precisely complementing and mating the mold pattern.

A further object of the present invention'is to provide a mold tamping apparatus ,which packs a mold in a minimum of time and requires little or no skill for its operation.

Still a further object of the present invention is to provide an improved apparatusV of the above nature characterized by its adaptability, simplicity, versatility, ruggedness and low cost.

The above and other objects Aof the present invention will become apparent from. a reading of the followingV description taken' in conjunction with the accompanying drawings, wherein:

FIGURE l is a fragmentary front perspective view of a mold tamping apparatus constructed according to and embodying the presentinventonfthe apparatus being illustrated in use;

FIGURE 2 is a fragmentary enlarged vertical sectional view of a portion thereof; and Y FIGURE 3 is 'a diagrammatic plan view showing the range of horizontal movement of a pair of adjacent tamping elements. p Y f In afsense, the present invention contemplates the provisionV of a mold treating apparatus comprising a plurality of horizontally spaced tamping elements, means supporting each of said tamping elements for substantially independent upward and horizontal movement, a mold support member disposed below said tamping elements, and means for vertically relatively reciprocating said support member and `said tamping elements.

According to a preferred form of the present apparatus there is provided a horizontally extending guide frame having a plurality of regularly transversely and longitudinally spaced vertical openings formed therein, and with it a support frame located above and aixed to the guide frame. A tamping element registers Witheach of the apertures in the guide frame, each tamping element being suspended by a flexible wire from the support frame at a point coaxial with the corresponding guide aperture. Each of the tamping elements is in the shape of a pestle, having a curved convex underface and an upwardly directed tapered shank registering with and of smaller transverse cross-section than the respective guide aperture, the suspending Wire extending from the top of the shank. The frame and pestle assembly is adjustably supported above a jolting table which carries a flask and a pattern of which a mold is to be made, whereby to effect vertical reciprocation between the mold and the pestles. In the alternative, means may be provided for vertically reciprocating the frame and pestle assembly.V The guide and support frames are vertically relatively adjustable, as are the lengths of the individual pestle supporting wires. The operation of the improved tamping apparatus will be hereinafter set forth.`

Referring now to the drawings which illustrate a preferred embodiment of the present invention, reference numeral 10 generally designates the improved tamper assembly which is illustrated in the process of forming a sand mold of a mold pattern 11. The tamper assembly includes an upper horizontal support frame or plate 12 and a lower, substantially coextensive, horizontal guide frame or grid 13. Guide frame 13 is in the form of a substantially flat square block, having formed therein a plurality of transversely and longitudinally equally spaced vertical bores or apertures 14 of transverse circular cross- Section. The upper border of each bore 14 is provided with .a curved peripheral ridge 1S and the face of the bore below theridge 16 tapers outwardly to thebottom 17 of the bore.

Support plate 12 is likewise of rectangular configuration and is mounted atop the guide frame 13 by means of turnbuckles 18 connecting aligned points adjacent to corresponding corners of frames 12 and 13. Each turnbuckle 18 includes a lower threaded rod 19 affixed, such as by welding, to the top face of the guide frame 13 and an upper rod Z0 threaded in a direction opposite to the rod 19 and projecting through an opening in the support place the threaded rods 19 and 20 and is releasably locked in position by a nut 24 engaging rod Ztl above coupling section 23. Thus, the distance between the support frame 12 and the guide frame 13 may be adjusted by loosening nuts 24, twisting coupiing sections 23 in a common selected direction and then tightening. the `nuts 24.

Formed in the support plate 12 in axial alignment with Y the guide bores 14 are small openings 26 adjacent each of which is a tapped bore. Engaging each of the aforesaidtapped bores is avscrew 27 carrying a lock washer assembly 2S above the support plate12. A flexible twisted multiple strand, preferably .steel ,wire cable 29 projects through each or" the openings 26 and has` its upper endV releasably locked to the support plate l2 by being clamped between the support plate top face and the confronting face of washer assembly 2S.

A pestlek shaped tamping element 3i? registers with each of the guide bores 14 and is suspended by and aixed to the lower end of a corresponding wire 29. Each of the tamping elements Sil is hollow and preferably formed of iron or steel. The tamping element underface 32 is of curved convex configuration and is joined by a relatively sharply curved peripheral side face 33 to an upwardly directed hollow shank 34 which is inwardly upwardly tapered to a top axial opening. Shank 34, along its entire length, is of lesser diameter than all portions of bore 14 so that the tamping element 30 is free to move vertically and horizontally and to rock therein to a degree limited by the relative dimensions of the guide bore 14 and shank 34. The wire cable 29 projects through the shank top opening into the pestle cavity 36 and has its bottom end unraveled and anchored to the pestle 30 by being embedded in lead or other suitable heavy material 37 disposed in the cavity 36. The weights of the various pestles 3) may varyin accordance with the amount of weighting material 37 contained therein. In order to facilitate the introduction of material 37 into cavities 36, openings 3S are formed in the upper walls of the pestle shanks The weights of the various pestles E@ in the assembly maybe different and their levels may vary by adjustment of the lengths of the suspending cables 29 to best suit the particular pattern 1l being molded.

The tamper assembly lltl is supported by an overhead hook 39 which is horizontally and vertically movable by any well known mechanism to permit the positioning of the tamper unit. Each of the hooks 21 engages the looped outerend of a connecting cable 4i), the inner end of which is looped through and connected to a coupling ring 41. Support hook 39 releasably engages ring 41 to adjustably support tamper unit l0.

Associated with the tamper unit and positioned beneath it is a vertically reciprocating or jolting table 42. Table 42 is vertically reciprocated by a jolting machine of any well known construction which maybe hydraulically, pneumatieally or otherwise motivated. The frequency and stroke of the jolting machine is adjustable in the conventional fashion. It should be noted, however, that the tamper unit 16 may be vertically reciprocated by any suitable mechanism either instead of or concurrently with the reciprocation of table 42.

In employing the tamping apparatus described above, the desired drag or cope pattern 11 which may be mounted on a pattern support plate 43 is positioned on the jolting table 42 and a conventional cope or drag ask 44 is also positioned on the table 42 in registry with pattern 11. Flask 44 may be, if desired, a snap ask. Advantageously, a separable upset frame 46, corresponding in outline to the ilask 44 is positioned upon the flask 44, being located thereon by suitable matching positioning elements. A granular mold material including a molding sand 47 is then poured into the ilask 44 and the upset frame 46 to a level above the bottom of upset frame 46. Tamper unit 10 is then lowered into registry with upset frame 46 and ask 44 to a level bringing the underfaces of the pestles Si? to below the level of the top of the finished rammed mold when the jolting table is in its topmost position. The jolting table is thereafter motivated to periodically reciprocate the pattern and flask assembly. As the sand-filled flask moves upwardly the surface of the sand is struck by the underfaces of the pestles to etlect the tamping or ramming of the sand and the upward movement and rocking of the pestles 30. Thus, upon the dropping of the table 42 with the sand-carrying ask each pestle 30 assumes a different horizontal position and angular orientation so that upon the next tamping stroke with the raising of the table 42 the pestles 30 strike the sand at different respective positions. As seen in FIGURE 3 of the drawing the center positions of the pestle underfaces 32 are shown in full line designated as 43, and various positions of the pestle underfaces of the two medial pestles there illustrated are shown in broken line and designated as 49. lt is to be noted that the areas covered by the various positions of each of the pestles overlap and the complete area of the iiask is engaged by the pestle underfaces in their various positions. After a short tamping period the sand is rammed into a compact, hard, uniform state forming a mold cavity precisely mating the pattern 1l. Thereafter, the upset frame is removed, the excess sand is struck off and the mold thereafter handled in the usual manner.

Employing the above apparatus it has been found that the tamping period for satisfactory mold formation is only a vary small fraction of that required with conventional ramming and tamping methods. Tamping periods of from six to eleven seconds have been found to be highly satisfactory. The subject apparatus can be used to advantage with almost any size mold and may be accordingly proportioned. The dimensions and weights of the pestles and their distribution and suspension are readily and easily determined and depend on the size and type of mold and pattern. For example, for general foundry practice for molds of approximately 24 by 24, pestles of the illustrated shape having a bottom face of 2 diameter have been highly suitable. The various other dimensions are substantially as shown in the drawings. The jolting frequency is advantageously between 1.5 and 2 jolts per each 10 seconds and preferably 1.7, and the length of the stroke is about 21/2, but may be varied to suit the size ot the mold and pattern. For smaller molding procedures, smaller pestles may be employed, of the order of as low as about 14; diameter and for larger molds the pestle diameters may be 6 or more.

it is important to note that a great problem in the ramming of sand molds is the horizon-tal tlow of the sand. This problem has been solved to great advantage by the mode of operation of the present apparatus. The gyrating pestles with the contoured undertaces effect radically increased ow-over that achieved by the vertical squeezing and ramming procedures heretofore employed. As a consequence, the mold ramming time is greatly re duced and a superior mold achieved.

While there has been described and illustrated a preerred embodiment of the present invention, it is apparent that numerous alterations, omissions and additions may be made without departing from the spirit thereof.

What is claimed is:

l. Amold treating apparatus comprising a plurality of horizontally spaced tamping elements, means supporting each of said tamping elements for substantially independent free universal movement, a mold support member disposed below said tamping elements, and means for verticallyrelatively reciprocating said support member and said tamping elements.

2. A mold treating apparatus comprising a plurality of horizontally spaced tamping elements having downwardly directed tamping faces, means supporting each of said tamping elements for substantially independent ree universal movement and limiting the horizontal movement ofV each of said tamping faces to a predetermined area, a mold support member disposed belowsaid tamping elements, and means or vertically relatively reciprocating said support member and said tamping elements.

3. rEhe mold treating apparatus ot claim 2, wherein adjacent ones of said predeterminedv areas overlap and delineate a continuous area.

The mold treating apparatus of claim 2, wherein said tamping faces are convex.

V5. The mold treating apparatus of claim 2, wherein said tamping elements are regularly longitudinally and transversely spaced.

6. A mold treating apparatus comprising a guide frame having a plurality of transversely and longitudinally Vspaced apertures formed therein, a plurality of tamping elements each of which has a downwardly directed tamping -face and an upwardly directed elongated shank slidably and rockably registering with a respective of said apertures, and means freely supporting said tamping elements with said Shanks in registry with said apertures.

7. A mold treating apparatus comprising a horizontal guide frame having a plurality of transversely and 1ongitudinally spaced vertical guide apertures formed therein, a support frame disposed above and mounted on said guide frame, a plurality of iiexible lines suspended from said support frame at points in vertical alignment with said apertures, and a tamping element having a downwardly directed tamping face and an upwardly projecting shank registering with each of said guide apertures and of smaller transverse cross-section than said corresponding guide aperture to permit the vertical movement and rocking of said tarnping elements in said apertures, said tamping elements being suspended by respective of said llexible lines.

8. The mold treating apparatus of claim '7, wherein 20 10. The mold treating apparatus of claim 7, including a vertically recipirocating jolting table located below said ramping faces.

111i. The mold treating apparatus of claim 7, includ ing means for individually adjusting the lengths of said flexible lines.

:12. The mold treating apparatus of claim 7, including means for adjusting the vertical spacing between said guide frame and said support frame.

References Cited by the vllxaminer UNITED STATES PATENTS 1,751,465 3/ 30 Breeden 22-41 2,959,828 11/60 lFrankenstein 22--41 2,963,755 12/60 Hesse et al. 22-43 FOREIGN PATENTS 1,095,753 12/60 Germany.

MICHAEL V. BRINDISI, Primary Examiner.

MARCUS U. LYONS, Examiner. 

1.A MOLD TREATING APPARATUS COMPRISING A PLURALITY OF HORIZONTALLY SPACED TAMPING ELEMENTS, MEANS SUPPORTING EACH OF SAID TAMPING ELEMENTS FOR SUBSTANTIALLY INDEPENDENT FREE UNIVERSAL MOVEMENT, A MOLD SUPPORT MEMBER DISPOSED BELOW SAID TAMPING ELEMENTS, AND MEANS FOR VERTICALLY RELATIVELY RECIPROCATING SAID SUPPORT MEMBER AND SAID TAMPING ELEMENTS. 